1. Field of the Invention
This invention relates to multi-chamber ink jet recording heads providing ink isolation and selective access to differing colors of ink in the respective chambers for printing text or graphics. More particularly, this invention is directed to a multi-chamber ink jet recording head having an improved nozzle plate employing nozzle formats in individual nozzle groups, corresponding to those of a single color recording head with which it is interchangeable.
2. Description of the Related Art
Ink jet recording heads are used in printers and plotters. These include thermal and piezoelectric types for expelling ink. The term printer as used herein is used as a term of convenience and is not intended to exclude other types of recording such as plotting.
Black ink is used in most printing applications, but there is a developing need for the use of colored inks in printing text and graphics. Heretofore, printers having recording heads designed for single color printing have not been retrofitted with color recording heads which may be interchangeably fittable in the printer carriage designed for the single color recording head, because of differing requirements resulting from pen body configurations, usually larger for accommodating several colors of ink, nozzle spacing and grouping, and control requirements, to name a few. While multicolor recording heads can be provided with a chamber for black ink, where a printer is predominately used for black text or graphics, a supply of black ink in a multicolor recording head fitting an all black or other single color recording head carriage mount is limited in volume. Thus interchangeable single color/multicolor recording heads in a printer increase the utility of an otherwise single color printer or recorder.
U.S. Pat. Nos. 4,511,907; 4,540,996; 4,611,219; 4,630,076 and 4,631,548 are related to this invention in the sense that they are all directed to multi-color ink jet printers. None of these, however, appear to teach or to suggest a configuration for a multicolor recording head which is interchangeable with a single color recording head in a single color printer.
U.S. Pat. No. 4,511,907 describes a color printer having a plurality of recording heads arranged in a horizontal direction, the nozzles in each being arranged in a vertical direction. The signals for printing are delayed for the second and subsequent recording heads by the time required for the carriage to move the distance between the first recording head and the second or subsequent recording heads.
U.S. Pat. No. 4,540,996 describes the positioning of a plurality of different color recording heads in the scan direction with respect to one another and the nozzles in each in terms of dot intervals for the purpose of defining an arrangement preventing double recording.
U.S. Pat. No. 4,611,219 describes a liquid jetting printer comprising a plurality of perforated plates providing two channel isolation with alternate ink passages for thermal ink jet operation.
U.S. Pat. No. 4,630,076 describes a multicolor recording head having horizontally spaced nozzle groups, each of which includes a row of nozzles inclined at an angle to the horizontal. An arrangement is described employing white or transparent dot over printing of a previously deposited color dot to cause color bleeding for achieving color tinting.
U.S. Pat. No. 4,631,548 provides a plurality of ink reservoirs for different colors of ink in an ink jet printer. Multicolor images are printed using the dot matrix principle. Dot diameter is controlled, either by adjusting the volume of ink in each droplet inversely with a number of droplets in a matrix dot, or preselecting a constant volume for the droplets and using the same number of the same or different colors of droplets in forming each matrix dot.
All of the patents aforesaid are related to this invention in the use of individual nozzle groups for differing colors and in the employment of dot matrix techniques for printing. None, however, are concerned with the interchangeability of a multicolor recording head with a single color recording head in a single color printer, particularly as to the arrangement of the nozzle formats in the respective nozzle groups for each chamber in the multichamber reservoir of the pen.